The report estimates solar owners will avoid 6.3m tonnes of carbon dioxide emissions in 2016, equivalent to taking a third of all trucks off Australian roads.
Photograph: Raoul Wegat/AAP

Australian households and small businesses have invested more than $1bn a year in rooftop solar over the past five years, spending a total of almost $8bn since 2007, new calculations show.

In its latest State of Solar report, Solar Citizens – which campaigns for, and represents the interests of, solar owners – has for the first time estimated Australian’s out-of-pocket investment in rooftop solar, how much money it has saved consumers, and how much carbon it has abated.

Overall, it found Australians have spent $7.8bn on rooftop systems since the 2007-08 financial year, an estimate based on the total amount of solar capacity installed and the cost of those systems.

Greens want 'fair price' for solar power and access to grid for all

Read more

In the past five years, that figure was more than $1.2bn each year – an investment that eclipses that spent on large-scale solar in most of those years, according to the report.

Those out-of-pocket costs didn’t include any subsidies or rebates solar owners received.

But since the 2012-13 financial year, Solar Citizens calculated solar owners saved about $1bn on their energy bills each year, with those in the Northern Territory leading the way, saving an average of $1,989 each in the 2014-15 financial year.

In total, solar owners have saved $4.4bn since the 2007-08 financial year.

Although 60% of solar owners said they primarily bought solar systems for financial reasons, 38% said they did so for environmental reasons, according to a poll of 4,300 Solar Citizens supporters from January.

And when it came to environmental outcomes, the report estimated solar owners will avoid 6.3m tonnes of carbon dioxide emissions in 2016 – which they found is equivalent to taking a third of all trucks off Australian roads.

The report tried to emphasise the political weight solar owners now have, with about 5 million people living in homes with solar systems.

Analysing the data in relation to federal seats, Solar Citizens found 80% of federal electorates have more voters with rooftop solar than would be required to change their sitting members. And of the electorates with the highest numbers of solar owners, seven out of the top 10 were now held by Coalition MPs.

Australian households have led the world with the density of small rooftop solar PV systems, about 16.5% of households now producing some of their own electricity. From 2006 to 2010, the number of solar systems installed each year in Australia trebled year-on-year.

“The growth is astonishing and it is fascinating that we can see, for the first time, what average Australians themselves have invested to ride this boom,” said Claire O’Rourke, national director of Solar Citizens.

“Australian political leaders need to understand just how much the average Australian themselves have committed of their own money to play a part in the transition of our power system,” she said.

“The global transition to renewables is already under way. Australia needs a national plan to harness the multi-billion-dollar renewables boom and manage the orderly transition to 100% clean renewable power.”

In April, Solar Citizens and GetUp! published a report advocating a range of policies intended to transition Australia to 100% renewable energy by 2030. It proposed changes in three broad areas: regulations, funding and obstacles to the rollout of renewable energy.

That report followed modelling the groups funded, produced by the institute for sustainable futures at the University of Technology Sydney, which suggested such a transition would be technically feasible and would save the country $90bn.